El Paso Border Patrol shooting murky

CIUDAD JUAREZ, Mexico 
U.S. and Mexican officials are trading suggestions of misconduct as the shooting of a 15-year-old Mexican by a U.S. Border Patrol agent on the border with Texas swells into a full-blown international incident.

Arturo Sandoval, spokesman for the Chihuahua state Attorney General's Office, says a shell casing was found near the body.

A U.S. official close to the investigation says a video shows what appear to be four Mexican law enforcement agents crossing the border, picking up an undetermined object and returning to Mexico. The official says on condition of anonymity the video shows the Border Patrol agent who shot the boy never entered Mexico.

The FBI said Tuesday the agent fired at rock throwers Monday evening.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

EL PASO, Texas (AP) - A U.S. Border Patrol agent shot and killed a 15-year-old Mexican boy after a group trying to illegally enter the U.S. threw rocks at the agents at an international bridge near downtown El Paso, authorities said Tuesday.

The shooting, which happened Monday evening, drew sharp criticism from Mexico, where the government said Tuesday that "the use of firearms to repel attacks with stones represents disproportionate use of force, particularly coming from authorities who have received specialized training."

According to the FBI, Border Patrol agents were responding to a group of suspected illegal immigrants being smuggled into the U.S. near the Paso Del Norte bridge, across from Ciudad Juarez, Mexico around 6:30 p.m. Monday.

One suspected illegal immigrant was detained on the levy on the U.S. side, the FBI said in a statement. Another Border Patrol agent arrived on the concrete bank where the Rio Grande would be if there was water flowing, and detained a second suspect. Other suspects ran back into Mexico and began throwing rocks, the FBI said.

At least one rock came from behind the agent, who was kneeling beside the suspected illegal immigrant he had prone on the ground, said FBI spokeswoman Andrea Simmons.

The agent told the rock throwers to stop and back off, but they continued. The agent fired his weapon several times, hitting one who later died, said the FBI, which is leading the investigation because it involved an assault on a federal officer. The agent was not injured, Simmons said.

Border Patrol Special Operations Supervisor Ramiro Cordero said preliminary reports show that Border Patrol agents on bicycle patrol "were assaulted with rocks by an unknown number of people."

"During the assault at least one agent discharged his firearm," he said. "The agent is currently on administrative leave. A thorough, multi-agency investigation is currently on-going."

Chihuahua State officials released a statement Tuesday demanding a full investigation into the death of the boy, identified as Sergio Adrian Hernandez Huereca.

The boy's sister, Rosario Hernandez, told Associated Press Television News that her brother was playing with several friends and did not plan to cross the border.

"They say that they started firing from over there and suddenly hit him in the head," she said Monday.